CD5 CAR T cells expand and downregulate CD5. (A) Schematic structure of CD5 CAR and transduction efficiency of primary activated T cells. (B) Expansion of activated T cells transduced with either Ctrl CAR or CD5 CAR. Data denote mean ± SD from 4 donors. (C) Surface expression of CD5 on NT T cells or T cells transduced with Ctrl CAR or CD5 CAR at 7 days post-activation. (D) Relative expression of CD5 messenger RNA in NT activated T cells or T cells transduced with CD5 CAR at 7 days post-stimulation. Ctrl CAR, control CAR; NT, nontransduced.